1. The Field of the Invention
The present invention pertains to a method and apparatus to rapidly measure the changing properties of flowing water, oil, and gas mixtures, and in particular to a system which takes very rapid, small volume measurements.
2. The Prior Art
There has been a great deal of effort put into the development and improvement of techniques for determining water cut and gas-fraction in oil/water/gas streams using dielectric probes in pipes of 2-inch diameter, or larger, containing a well mixed fluid In this content, "well mixed" means that the fluid is homogeneous with respect to the two inch pipe volume and that the time scale is less than one second. While it is possible to determine gas-fraction and water cut with a dielectric measure of a homogeneous mixture of the oil/water/gas stream, this homogeneous mixture measurement is often augmented by another measurement, such as a density measurement, to determine water cut and gas-fraction. Examples of this can be found in U.S. Pat. No. 5,101,164, the disclosure of which is incorporated herein by reference.
The present inventors have discovered that despite large scale homogeneity, there also is small scale heterogeneity which can be exploited to great advantage by making a large number of rapid small scale measurements.